Resumo. Abstract: The pughead condition is a cranial deformity characterized by a shortened upper jaw relative to the lower jaw. In this study, we report the occurrence of this deformity in a single specimen of the Demon Eartheater, Satanoperca jurupari, collected in the Lower Rio Tocantins Basin. The most affected anatomical regions include the upper jaw, suspensorium, and anterior portion of the neurocranium. Although pollution from agrochemicals used in palm monoculture near the collection site is a plausible contributing factor, no direct evidence currently confirms this as the cause. This report represents the first documented case of the pughead condition in Satanoperca and the first record of this deformity in a species from rivers of the Brazilian Shield.